US1392057A - Control system - Google Patents

Description

4 SHEETS-SHEET 1.

INVENTOR Hen/jy@ Jn/@.5

BY v

ATTRNEY H. D. JAMES.

CONTROL SYSTEM.

APPLICATION FILED AUG.I0, 1918.

Patented Sept. 27

-WITNESSES t @uw w JM H. D. JAMES.

CONTROL SYSTEM.

APPucATloN FILED Aue.1o,|91e.

Pamd sept. 27,1921.

4 SHEETS-SHEET 2.

WITNESSES:

, I v INVENTOR Henry D. James ATTORNEY H. D. JAMES.

CONTROL SYSTEM.

APPLICATION mio Ammo, |918.

1,392,057, Patented Sept. 27, 1921.

4 SHEETS-SHEET 3.

F/y. 8 i Z W|TNESSES INVENTOR Hen/y D. James ATTORNEY H. D. JAMES.

CONTROL SYSTEM.

APPLICATION man Ammo, 191s.

1,392,057, PatentedSept. 27, 1921.

4 SHEETS-SHEET 4.

WITNESSES:

- INVENTOR /wwf Hen/ g D, Jam

. v BY ATTORNEY UNITED STATES PATEN'I" OFFICE..

HENRY D. JAMES, OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF IEE1\T1\`|'SYI VANIA.

CONTROL SYSTEM.

Application led August 10, 1918. Serial No. 249,344.

T 0y all whom t may concern Be it known that I, HENRY D. JAMES, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Systems, of which the following is a specification. Y

My invention relates to reversing systems for electric circuits, especially electric motors, and is particularly adapted for use in vconnection with motor-control systems of the character set forth in my copending application, Serial No. 236,937, filed May 27, 1918, control systems.

The dominant feature of the systems of my said application is that a coil designed to actuate the relays for controlling the contactors which short-circuit the accelerating resistor is shunt-connected across the terminals thereof. The relays may be of the type illustrated in a copending application by De Camp, Serial No. 241,259, filed June 21, 1918, and assigned to the Westinghouse Electric & Manufacturin Co., or they may be of any ordinary type. n the latter event, a separate actuating coil may be employed for each relay, all the coils being connected in multiple with the resistor.

As explained in my above-mentioned application, means must be provided, owing to n object of my invention is to provide a.

safe starting system for a motor so controlled.

Another object of my invention is to provide a reversing system for a motor governed by such a controlling system.

Other objects yof my invention will be made clear hereinafter.

If relays be employed of the type described 'in the aforementioned application by De Camp, in which a main armature controls the closing of the relays, I may so arrange the control circuits that it will be impossiblethe motor is started. I may effect this object.

electrically or mechanically.

If the mechanical method be employed, the main armature may be so designed as to be actuated to its normal position, upon the reversal of the motor, by a projectlon carried by a bar connecting the reversing contactors. If the electrical method be adopted, the main armature may, itself, be a contactbearing member, the contact members of which may initially close the motor circuit when the armature member occupies its normal, inoperative position, after which the Contact members may be short-circuited so as not to break the starting circuit upon the actuation of this armature member to its operative osition.

I have e-rein illustrated several systems embodying this principle. The circuits may be so arranged as to prevent the reversal of the' motor until after a time interval has elapsed, caused by the Areversal of the magnetism of the coil for controlling the relays. I have also illustrated one lmethod of revensing a motor the acceleration of which is effected by the use of ordinary relays having individual actuating coils. y

My invention will vbe understood by reference to the accompanying drawings, in

which Figures 1, 2 Yand 3 are,y respectively, a

side and an end elevation and a plan view of a relay of the type illustrated in the aforementioned application by De Camp.v

Fig. 4 is a detail kof a modification of this v relay. Fig. 5 is a diagrammatic view of clrcuits and apparatus illustrating one form of my invention as applied an accelerat-f ing` system employing a relay of the type shown in Figs. 1 to 3. Figs. 6 and 7 are similar views of modifications. F ig. 8 is a modified system employing a relay, a detail of which is illustrated in Fig.. 4. Fig. 9 is a reversing system, arranged according to my invention, employing ordinary relays.

As' my invention is of particular value in connection with a system employing the De Camp relay above referred to, and illustrated in Figs. 1 to 4 it Will conduce to clear-,.

ness to describe this relay first.

An insulating panel 29 carries two brackets 30 and 31 supporting the coils 22 and 23 which, when energized by currentl flowing through them, create magnetic fields for attracting an armature 32 and armatures .33, 34 and 35. A compression spring 36 is adjustably mounted upon a non-magnetizablel rod 37 that is slidably mounted in projections 38 and 39 which are integral with a member 31. The projection 38 'serves also as a pole piece for the armature 32 and the projection 39 as a pole piece for the armatures 33, 34 and 35. A bar 40 is rigidly -connected to the rod 37 and normally enby a relatively weak spring 43. The bracket 30 supports a non-magnetizable U-shaped member 44 between the arms of which are pivotally mounted the armatures 33, 34 and 35, which carry, respectively, the movable Contact members 45, 46 and 47 of the relays 25, 26 and 27. The corresponding stationary , contact members 48, 49 and 50 are mounted upon the insulating panel 29.

Springs 51 are attachedto longitudinally adjustable members 52 and to the other ends of the members 41. The pole piece 39 is f, ber 56 may be replaced by a switch vmemberv provided with longitudinally adjustable members 53 to regulate air gaps 70 between these members and the corresponding armatures. By means of this adjustment, or by means of the -members 52, which control the `tension of the springs 51, the action of thc magnetic fluxproduced by the coils 22 andl 23 may be so regulated that the armatures 33, 34 and 35 will be operated in proper sequence.

v The armature 32 is provided with an extension 54 of insulating material which carries a switch member 55 for coperating with stationary switch members 5,6 mounted upon the insulating panel 29. As shown in Fig. 1, the switch members 55 and 56 .are closed when.- the armature 32 occupies itsl open position. If desired, ythe switchmem- 57 Fig. 4, so that contact between the switch members 57 and 55 Vwill be madeywhen the armature 32 occupies its closed position.

The operation may be briefly described as follows: Upon current flowing through the coil 22, a magnetic field is created which [causes .the armature. 32 to be attracted to- 'ward the'pole piece 38. The for'ce'of the spring 36 is thereupon overcome, and the `trated in Fig. 5.

Amembers 55 and 56.

lof successive portions 13, 14 and 15 of the bar 40 is moved out of engagement with the armatures 33, 34 and 35, the stop members 41 of which are, nevertheless, maintained in engagement with the pole piece 39 until the flux of the magnetic field becomes successively sufliciently low to permit the springs 51 to successively actuate the movable contact members 45, 46 and 47, thereby to close v the relays 25, 26 and 27.v In the event that the magnetic field 'becomes too weak to hold 75 the armature 32 in its elevated position, the spring 36, becoming released, will separate the movable from the stationary contact members. Actuation of the armature 32, of

course, effects corresponding actuation of the switch member 55.

I shall now describe the invention illus- A motor, the armature of which is shown at 1 and the shunt fieldmagnet winding at 2, is connected between line conductors 3 and 4, with a regulating resistor 6 normally in series with the armature 1. A plurality of reversing contactors 58, 59, 60 and 61 control the direction of rotation of the motor. A master controller or switch 7 controls the actuation of the reversing contactors through the medium oi energizing coils 62, 63, 64 and 65, which are connected in lcircuits including the contact members 55 and 56.

The movable contact members of' contactors 66 and 67 are, respectively, mechanically interloc'ked with the movable contact members of the reversing contactors 58 and 59 to provide shunt circuits for the contact rlhe master controller` 7 is designed to close contact members 9 and 18. One or more contactors 10, 11 `and 12 (three are illustrated) control the shunting y,

regulating resistor 6 through the medium of energizing coils 19, 20and 21. The coil 22 is connected across the terminals of the resistor 6. at 79 and 80. The energizing of the coil 22 causes the successive closing of the 110 relays 25, 26 and 27, as above described, in accordance with the strength of the current passing through the coil 22.

The coil 19 is connected in a circuit lead- .ing from the line conductor 3, bythe conductor 28, through thev reversing contactor 59, (assuming this contactor and the contactor 60 to be closed) the armature 33 and the relay 25 to` the point 79 and from that point, through the reversing contactor 60 120 to the line conductor 4. If the reversing contactors 58 and 61 are closed instead, the current thrOugh the coil 19 is in the reverse direction. The coils 20 and 21 are similarly connected to the relays 26 and 27., The coil 125 23 is connected, vby conductor 28,l in parallel with thecoil 21 and in series with a high resistance 24, so that the current in the coil 23, likel that in the coils 19, 2O and 21,

is reversed when the motor is reversed.

Upon moving the controller 7l to the left, a'circuit is established from the line conductor 3 through the controller arm 7, which is electrically connected thereto, the con- 5 tact member 9, the coils 63 and 64 in parallel, one'of the contact members 56, the contact member 55 and the other contact member 56 to the line conductor 4, The coils 63 and-64 are. thereupon energized -to 1o cause the closing of the reversing contactors `59 and 60. A circuit -is now established extending from the line conductor 3, by the conductor 28a, through the reversing contactor 59, the motor armature 1, the resistor 6, the point 79 and the reversing contactor 60,v to the line conductor 4. A. shunt circuit is` established through the field-magnet winding 2 when the main-line switch (not shown) is closed. A circuit is also established through the coil 22 in parallel relation to the resistor 6, the coil 22 and the resistor 6 being-connected at - points 80 and 79.

The energizing ofthe coil -22 creates a 25 magnetic lfield which attracts the armature 32y to the pole piece 38 andwinstantly separates the contact members 55 and 56. This separation breaks the circuit, above described, of the coils 63 and 64." Holding circuits for these coils have previously been established, however, b the contactor 67, mechanically interlocke with the reversing contactor 59. The rod 37 is actuated by the armature 32, in opposition to the Jforce of the spring 36, to force the bar 40 away from the armatures 33, 34 and 35.

If the current is above a previously-selected safe value, the flux of the magnetic vfield created by the coil 22 will overcome 40 'the forces of thesprings 51, and the armatures 33, 34- and 35 will remain with the stops 41 in engagement with the pole piece 39 (Fig. 1). As the motor accelerates and the current decreases in value the magnetic 45 flux set up by the -coil 22 diminishes..

When the i'luX has decreased to a predetermined yvalue, the spring '51 attached to the armature 33 will overcome the force VeX- erted bythe flux of this field so that the relay 25, controlled by the armatureV 33, will be closed. The time when this operationwill occur will depend upon the width of the air gap 70 and the tension v.of the spring 51. The armatures 34and 35, however, will remain open; The closing of the relay 25 4establishes a circuit which extends from the.

line conductor 3, by the conductor 28a, through the reversing contactor 59, the armature 33, the contact members 45 and 48 0 of the relay '25, and the actuating coil 19 to the point 79 and fromthere, through the reversing contacter 60, to the llne conductor 4. 'The coil .19 becoming energized.the contactor 10 becomes closed to short-circuit, the

portion 13 of the resistor 6. The motor then further accelerates, and, by'decreasing the voltage across the terminals of the coil 22, the magnetic field in the neighborhood of this coil is further weakened which permits the closing of the second relay 26 con-- trolled by the armature 34. ,A circuit is then made from the line conductor 3, by the) conductor 28a, through the reversing contactor 59, the armature 34, the contact members 46 and 49, the coil 20 and the reversing'contactor 60 to the line conductor 4. The coil 20, thus becoming energized, causes the closing of the contactor 11 and the consequent shunting of a second portion 14 of the resistor 6.

After the motor has accelerated further, the magnetic field surrounding the coil 22 is again weakened and the relay 27 is closed, creating a circuit extending from the line conductor 3, by the conductor 28a, through the reversing contacter 59, the armature 35, the contact members 47 and 50, 'the coil 21 and the reversing contactor 60'to the line conductor 4, thereby causing the closing of the contactor 12 and the shunting of the third portion 15 of the resistor 6.` The whole resistor 6 is then entirely shunted from the armature circuit and the armature 1 is oon-- nected directly across the line.

The shunting of the resistor 6 denergizes the coil 22 which would release the armature 32 and cause the relays 425, 26 and 27 to be re-opened, thus resulting in de'nergization of the coils 19, 20, and 21 and the consequent re-insertion of the resistor 6 into the armature circuit, except for the coil 23, which becomes energized at the same time with the coil 21 upon the Iclosing of the armature 35 of the relay 27. The coil 23 is connected in a circuit extending from the line conductor 3, by the conductor 28a, through the reversing contacter 59, the darmature 35, the contact members 47 and 50, the 'conductor 28, the coil 23, the -resistor 24, the point 79 and the reversing contactor 60 to the line conductor 4.

The motor may be stopped by moving the controller army 7 to the of position illustrated, thereby denergizi-ng the actuating coils' of the reversing contactors and the consequent opening of the reversing. contactors. The coil 23 is, thereupon, denergized (which lthereupon permits the opening of the relays 25,26 and 27 as are also the actuating coils v19, 20 and 21 of the contacf tors 10, l1 and 12. The motor may thenA be restarted, eitherin the same or -in the tactors will l'yv open. Upon reclosing the controller arm 7, within a limited time thereafter, while the armature 1 is still rotating, the coil 22 is again energized, above the predetermined degree at which the relays 25, 26 and 27 are permitted to close and cause the reclosing of the contactors 10, 11 and 12 to short-circuit prematurely the entire resistor 6. This tends to have the effect of suddenly throwing the armature 1 into the line circuit without any resistance in series with it. In my copending application above mentioned, as also in Figs. 6 and 7 of the present application, are illustrated several 4methods for preventing this happening. The present application is more concerned with the preventing of similar occurrences upon the'reversal of the motor from Jfull speed in one direction to full speed inthe opposite direction. 2 i

.Assuming that the motor -is operating at full speed and that it is desired to reverse it, the controller arm 7 is moved from, let us say, the extreme left-hand position to the extreme right-hand position of Fig. 5. The circuits of the motor are thereupon opened, as explained above, and a new circuit is established from the uline conductor 3 through the controller arm 7, the contact member 18, the actuating coil 62 of the reversing contactor 58 and the actuating coil of the reversing contactor 61 in parallel. and the contact members 55 and 56, if closed, to the line conductor 4. v

The contact members 55 and 56, however, will not be closed until'the coils 22 and 23 are sutliciently denergized. rllhe residual magnetism of one or both of these coils may maintain the armature 32 open, and the relays 25, 26 and 27 may, therefore, remain closed 4for a limited period oftime. Upon the closing of thecontact members 55 and 56 and the establishment of the above-traced circuit, a circuit is established for the motor which extends from the line conductor 3, by the conductor 28h, the reversing contactor 61, the resistor 6, the armature 1 and the. reversing contactor 58,v to the line con`- ductor 4, the circuit being, in this case, in a direction reverse to that described above.

.The coil 22 is energized in the same manner as above described, but the connections of its terminals are reversed, to cause the closing4 of the armature 32 and the consequent release by the bar 40 of the armatures 33, 34 and 35. The motor is now started in the opposite direction, but with the whole resistor in series with the ar'- mature. The relays will not close simultaneously, as might happen, in the absence of special provision thereagainst, if the motor were restarted in the same direction by reason, of the reversal of -coil 22.

0 polarity of the The decreasing current in the coil 22 will, as before, cause the closing of the armatures 33, 34 and 35 to cause the closing of the contactors 10, 11 and 12 to short circuit the resistor 6.

It will thus be seen that, with the system of Fig. l5, the purpose of my invention, namely, to prevent a reversal of the motor with the resistor short-circuited from the armature circuit, is accomplished in several'ways. The circuits are so arranged that it is impossible, owing to the contact members 55 and 56, to effect the closing of either pair of the reversing switches untily the energization of the coil 22 hasy decreased to a predetermined degree. Frovision is made, also, for reversing the magnetic fields of the coils 22, 23, 19, 20 and 21 when the motor circuit is completed 'for operation in the opposite direction.

Another method of effecting this result is illustrated in Fig.6. The coils 19, 20 and 21 are here directly controlled by the controller 7, through contact members 16 and 17, instead .of through the reversing contactors. The coil 19 is connected in circuit as above described. The circuit of the coil 20, however, extends from the line conductor 3 through the controller arm 7, the contact member 16 or 17, the armature 34 and the relay 26, to the connecting point 68 of the resistors 13 and 14. When the resistor 13 is included in the circuit of this coil 20, the voltage is not sulicient to energize the coil 20, and the contactor 11, therefore, remains open. When the contactor 10 is closed, the

circuit is completed to the line conductor 4 through this contacter, and the coil 20 becomes suiciently energized to close the contactor 11. Similarly, the coil 2l is connected at 69 in a circuit which includes the relay 27 and the resistors 13 and 14, except when the contactor 11 is closed, thereby delaying the closing of the contactor 12 until `the contactor 11 is closed.,v r

A line contactor 5 is employed in addition to the reversing contactors 58, 59, 60 and 61, the coil 8 of which is in parallel circuit with the coils 19, 20 and 21. The reversing contactors 61 and 60, like the contactors 66 and 67, are here shownmechanically interlocked with the reversing contactors 58 and 59, respectively, though separate reversing contactors may, if desired, be employed, as in Fig.` 5. The coils 22 and 23 are here shown as continuous, though this is merely a detail.

The operation is as follows: Upon actuatlng the contro-ller arm 7 to the left, a circuit is established which extends from the line conductor 3, through the controller arm 7, the actuating coil 63 of the reversing contactors 59 and 60 and the contact members 55 and 56 to the line conductor 4. The reversing contactors 59 and 60 are thereupon closed to establish the motor circuit, which extends from the line conductor 3, by the conductor 28a, through the reversing contactor 59, the armature 1 and the reversing contactor 60 to the point 80 and from there, throu h the resistor 6 and the line contactor 5 to t e line conductor 4.

The line contactor 5 is closed because of the energizing of the circuit including the coil 8 and the contact member 16. As above described, the coil 22, which is connected in parallel with the resistor 6, will cause the closing of the armature 32 and later, the suc- (Lessive closing of'the armatures 33, 34 and 35. The closing of the armature 32 separates the contact members55 and 56, but a holdingA circuit for the coil 63 is previously closed at 67. This circuit extends from the line conductor 3, through the controller arm 7, the contact member 9, the coil 63, and the contactor 67 to the line conductor 4.

Theclosing of the armature-33 establishes a circuit which extends from the line conductor 3, through the controller arm 7 the contact member 16, the armature 33, the contact members 45 and 48 of the relay 25, the coil 19, the point 79 and the line contactor 5, to the line conductor 4, whereupon the line contactor 10 closes to short-circuit the portion 13 of the resistor. 6. The motor circuit now extends through thereversing contactors and the armature 1, as above described, through the portions 15 and 14 of the resister 6, to the point 68, and from there, through the contactor 10, to the point 79, and

= from there, through the line contactor 5, to

the linev conductor 4.

lUpon the closing oit the armature 34,'due to the decreasing magnetism of the coil\22, a circuit is established which extends from the line conductor3, through ,the controller arm 7, the contact member 16, the armature 34, the relay 26 and the coil 20, to the point 68 and from there, through the resistor 13 and the contactor 5 to the line conductor 4. As stated above, the voltage of this cir# cuit is not sufficient to cause the closing ot the contactor 11. If, however, the contactor 10 is closed, thenthe above-described circuit continues romthe point 68, through the contactor 10 to the point 79' and through the line contactor 5 to the line conductor 4,

whereupon the contactor 11 becomes closed to short-circuit'the resisto-r 14.

Similarly, the closing of the relay 27 will cause the energization of the coil 21 to cause the closin of the contactor 12, and the consequent s ort-circuiting of the resistor 15.

,The armature circuit will then extend from the line conductor 3 by the vline conductor 28a, through the reversing contactor 59, the armature 1,..the reversing contactor 60,.the

j contactor 12, the point 79 and the contactr 5, to the line conductor 4. l

The closing of the relay 27 establishes not only the circu`t of the coil 21 but also that of the coil 23. `his latter circuit extends the resistor 24 and the coil 23, to the point 79, and thence, through the line contactor 5, to the line conductor 4. `Thecoil 23 thus takes up the work of the coil 22 upon the short-circuiting of the lattercoil coincident with the 'short-circuiting of the resistor 6.

If it is desired to'reverse the motor, the arm 7 is actuated to the right to make contact with the contact members 17 and 18. The circuit of the coil 8 is broken at the contact member 16 but is immediately restablished at the contact member 17. The actuating coil 63 becomes denergized, but the coil 62 becomes energized, due to the closing of a circuit extending from the line conductor 3, through the controller arm 7, the contact member 18, the coil 62 and the contact members 55 and 56, if closed, to the line conductor 4. The switch members 55 and 56, however, will remain open until the magnetism of the coil 23 has su'ficiently diminished to permit the armature 32 to be opened by the spring 36 (Fig. 1). The relays 25, 26 and 27 will also be opened by this spring. The coil 22 becomes renergized as soon as the motor circuit is closed. This circuit eX- tends from the line' conductor 3, through the conductors 28a and 28", the reversing contactor 61, ii' closed, the armature 1, the reversing contactor 58, the resistor 6, and the line contactor 5,-to the line conductor 4. The connections of the coils 22 and 23 are not reversed as in the system of Fig. 5 and there is not, therefore, the protecting feature of time lag by reason of the reversal of the corresponding magneticgfields. rlhe protection of the motor is atorded by the fact that, in the event that the coil 22 is suffif Acie/n tly energized to cause the premature `closing of the armatures 33,34 and 35, the

contactors 10, 11 and 12 will not close simultaneously,`even though the circuits of the coils 19, i20 and 21 be simultaneously closed by the closing of the relays 25, 26 and 27. The coil 20 cannot become su'liciently energized to cause the closing of the contactor 11 until the contactor 10 has closed and not until the contactor 11 closes can `the coil 21 cause the closing of the contactor 12.

The sys ems of' Figs. 5 and 6 have the feature in co mon that it'is impossible to restart or reverse the motor until the armature 32 occupies its normal position and this it lock shall be mechanical. I have shown in Fig. 7.

The reversing contactors 58' and 59 of this figure are mechanically interlocked in a well known manner by a bar 72, pivoted at 73, and the ends of which are pivotally connected to the reversing contactors. The bar is provided with a central projection 74 adapted to engage a spring-pressed rod 75, slidably mounted in brackets 76 and 77 and the end of which is adapted to engage a projection 78 rigidly secured to the armature 32. The parts are so arranged that, upon the actuation of the reversing oontactors from one position to another, the projection 74 will engage the rod 75 to Jforce it downwardly into contact with the projection 78 and thereby cause the opening of the armature 32.

This action releases the spring 36, (.Fig. 1) whereupon the bar 40 causes the openin of the armatures 33, 34 and 35. rl`he Such a system `coils 19, and 21, are denergized which insures that the whole resistor will be in circuit with the armature before the motor is reversed. A drum controller 7 'has been illustrated in this ligure, though the controller of Figs. 5 and 6 may be employed and, conversely, the controller of this iigure may be employed in the systems of Figs. 5 and 6. ln this connection, it may be stated that, if the reversing contactors of Fig. 5 were mechanically interlocked with the armature 32, it would be possible to do away with the necessity of employing the contact members and 56 and the interlock contactors 66 and 67.

The operation of this system is as follows:

Upon the actuation ofthe controller to the left to position a, a circuit is established which extends lfrom the line conductor 3, through the actuating coil 63, the contact member 9 and the controller 7 to the line conductor 4. The coil 63 is accordingly energized to cause the closing oi the reversing contactors 59 and 60. A circuit is then established which extends from the line con? ductor 3, by the conductor 28a, through the reversing contactor 59, the armature 1, the reversing contactor 60, and the resistor 6 to the line` conductor 4. j

The bar 72 is, at the same time, actuated by the coil 63 about its pivot 73 to remove the projection 74 from engagement with the rod to free the armature 32 which will be closed by the coil 22, the terminals of which are connected across the resistor 6 at the points 79 and 80. llVheii the controller is actuated to the position b, a circuit is established which extends from the line cond-uci tor 3, through the armature 33, the contact members 45 and 48 of the relay 25, the actuatingcoil 19 and the contact member 16 to the line conductor 4, assuming, of course,

c that the armature 32 has been actuated to tst.

closed position by the coil 22 and the armature 33 by the spring 51 (Fig. 1).

llii similar fashion, the coils 2O and 21 are laterjclosed at the proper time according to the degree of ncrgization of the coil 22,

ductor 3, through the conductor 28 and' the resistor 24, to the point 80. l

The coil 23 may be energized by line voltage, as in Figs. 5 and 6, or the systems of these two gures may be so arranged that the coil 23 of these figures will be energized bv the counter-electromotive force of the niotor. The armature 32 will thus be maintained in closed position and the relays 25, 26 and 27 will remain closed to maintain the resistor 6 short-circuited. The controller 7, of course, may be actuated 'step-by-step or to the'position d in one step.

f To reverse the motor, the controller 7 is moved in the'opposite direction, either stepby-step or to the position d in one step,

whereupon the coil 62 will be energized to cause the closing of the reversing contactors 58 and 61. IThe coil 63 becoming denergized, the bar 72, actuated by the coil 62, will cause the positive opening of the reversing switch 59 in opposition to the force of the spring-pressed bar 75 and it will furthermore actuate this spring-pressed bar to cause the opening ot the armature 32 and, therefore, the o ening of the relays 25,

26 and 27. This action will have the effect oi ree-inserting the resistor 6 into the armature circuit, which now extends from the line conductor 3, by the conductor 28h. through reversing armature 1, the reversing contactor 58 and the resistor 6 to the line conductor 4.

The motor will now be o erated in the opposite direction. rllhe co1 22, however, will be energized in the same direction and, it the Vreversal take place within a Sulliciently limited period or time, the coil 22 will be suciently energized to cause thepremature closing of the relays 25, 26 and 27. This may be prevented, however, by either the electrical interlocking feature illustrated in Fig., 6, consisting of tapping the circuits of the coils 20 and 21 at (iS-.and 69 or by a mechanical interlocking device diagrammatically illustrated in. Fig. 7 at 81 and 82.

The mechanical interlocking device coinprises so arranging the relays and contactors that, when the contactor 10 is open,

he relay 26 will. be open and., when the'con- 130 contactor ei, the 11o contactor but not until the contactor 10` is closed can the relay 26 close to cause the closing of the contactor 11. Similarly, not

until the contacter l1 has'closed can the relay 27 be closed to cause the closing of the cntactor 12. l

It is essential that, in the systems of Figs. 5 and, the circuits of the reversing contactors be closed in the open position of the armature 32. In Fig. 8, I have illustrated a system in which the reversing contactors are closed when the armature 32 occupies its closed position. In the system of this ligure the relay is employed, a detail of which is shown in Fig. 4, the contact members 55 and 57 being open when the armature 32 is open and closed when the armature 32 is closed.

A pair of reversing contactors, of the type illustrated in Figs. 6 and 7, are employed. They are shown interlocked by a bar 72, as in Fig. 7, though this bar is not absolutely essential. A similar bar is preferably employed also in the systems of the other igures. If desired, such a bar may be employed in connection with the systems of Figs. 5 and 6. The controller 7 is here shown as comprising three contact members, insulated from each other, adapted to cooperate with statioi'iary` contact members on each side thereof for direct and reverse operation, respectively. 'llwo of the contact members are designed to close before the third, although the controller may be so op erated as to close allot the contact members together. The controller is preferably ot the drum type, as in Fig. 7, but any other type o't controller may be employed if desired. rlhe motor shown in this gure is of the series-field type, but it may be of the shunt-field or compound type. The motors of the systems of the other figures may also be either series or compound.

A line contactor 5 is employed in addition to the reversing contactors, as in Fig. l6, the actuating coil 8 of this contacter being controlled by the contact members 55 and 57. 4 contactor 83 is mechanically interlocked with the contactor 5 for a purpose later described.

, Assuming that the controller 7 has been moved one step to the left, a circuit is com-l pleted which' extends :from the line conductor 3 through the contact member 9a, the actuating coil 63 and the series field-magnet winding 84 to the line conductor 4. The reversmg contactors 59 and 60 are thereu on closed, whereupon a circuit is establis ed r from the line conductor 3, through the reversin contactor 59, the contact member 9b,

lthe coll 23,' the resistor 24, the contacter 83,

the conductor 85, the conductor 71, the reversing contactor 60 and the series fieldmagnet winding 84, to the line conductor 4.

The armature 32 is nthereupon closed, ,f

which closes the contact members 55 and 57, whereupon a circuit is yestablished from the line conductor 3, through the reversing contactor 59, the contact member 9", the actuating coil 8, the contact members 57 and 55, the conductor 71, the reversing contactor 60 and the series field-magnet winding 84, to the line conductor v4. rlhe line contactor 5 is thereupon closed to establish the motor circuit :which extends from the line conductor 3, through the reversing contacter 59, the armaturell, the line contactor 5, the resistor 6, the reversing contactor 60 and the field-magnet winding 84 to the line conductor 4.

The closing of the contactor 5 causes the opening of the contactor 83, which deenergizes the coil,23. circuit is, at the same timeestablished across the terminals of the resistor 6 for the coil 22, which eX- tends from the point 8O to the point 79. The armature 32 is thus initially closed independently of the coil 22. 0n the other hand, the coil 23 is energized but a brief period, so as not to serve to maintain the relays 25, 26 and 27 open. The coil 22, however, will cause :themto close in the manner previously described. l

Upon the closing of the relay'25, assuming that the controller 7 has been actuated to its final position, a circuit is established which extends from the line conductor 3, through the reversing contactor 59, the contact member 16, the actuating coil 19, the contact members 48 and '45, the armature 33, the conductor 71, the reversing contactor 60 and the series field-magnet winding 84, to the conductor 4. This causes the closing of the contacter l0 and the consequent short-circuiting of the resistor 13. Similarly, the closing of the relay 26 causes the closing ot the cont-actor 11 to short-circuit the resistor 14, and the closing of the relay 27 causes the closing of the contactor12to short-circuit the resistor 15. The closing of the relay 27 establishes also the following circuit: from the line conductor 3, through the; reversing contacter 59, the contact member 9b, they coil 23,xthe resistor 86, therelay 27, the armature 35, the conductor 71, the reversing contactor 60 and the field-magnet winding 84, to the conductor 4. The circuit of the coil 23 is thus restablished to maintain the relays closed, though theI coil 22. is denergized upon the short-circuiting ofthe resistor 6. The motor is now connected directly acrossV the line conductors- 3` and 4.

To reverse the motor, the controller 7 is moved in the opposite direction. The circuits above described are thereupon broken reverse direction. l

n new circuits are made at the contact meinbers 18, 18b and 17. A circuit is first established which extends from the line conductor 3, through the contact member 18a, the actuating coil- 62, and the series field-magnet winding 84 to the line conductor 4, whereupon the reversing contactors 58 and 61 are closed to partly close a circuit extending from the line conductor 3 throu h the reversing contactor 61 to the point 9, thence through the resistor 6, the line contactor 5, whichis open, the armature 1, the reversing contactor 58 and the field-magnet winding 84 to the line conductor 4.

A circuit is established from the line conductor 3, through the reversing contactor 61, the conductors 71 and 85, the contactor 83, the resistor 24, the coil 23, the contact mem- 'ber 18", the reversing contactor 58 andthe field-magnet winding 84, to the line conductor 4. The coil 23 will thereupon be energized by a current in a direction opposedto that flowing when the motor was operating in the other direction. Thearmature 32, therefore, will not be actuated until it is irst returned bythe spring 36 1) to its open position, when the magnetism produced by the newly created current in the coil 23 overpowers the residual magnetism of the coil 22.

rllhe armature 32 will then be reac'tuated to closed position when the current inthe coil 23 builds up to a larger value. As soon as the armature 32 has been returned to its normal position, a circuit is established eX- tending from the line conductor 3, through the reversing contactor` 61, the conductor 71, the contact members 55 and 57, the actuating coil 8, the contact member 18h, the reversing contactor 58 and the held-magnet winding 84 to the line conductor 4, causing the opening of the contactor 83 and the closing of the contactor 5 to establish the motor circuit above described. Current now, traverses the motor circuit in the opposite direction.

The establishing of the motor circuit, of course, causes the reversal of current in the coil 22, so that any residual magnetism must rst be overcomenbefore the coil 22, which now performs the function of the coil 23, the circuit of which was broken at the contactor 8.3, can be suiiiciently energized to actuate the armatures 32, 33, 34 and 35, thus `providing for the lapse of a sufficient time circuits of the actuating coils 19, 2O and 21 will also be found to be traversed byl current flowing in a direction opposed to that flowing when the motor was operating inthe The circuit of the actuating coil 19, for

i example, extends from the line conductor 3,

lthrough the reversing contactor 61, the conductor 71the armature 33, the relay 25, the coil 19, the contact member 17 the reversing contactor 58 and the field-magnet winding 84, to the line conductor 4. A certain time interval will elapse beforethe current in this circuit will energize the coil 19 suiiciently to overcome the residual magnetism of this coil, during which interval of time the contactor 110 must be open. It will later close to short-circuit the resistor 13. Similarly, the contactors 11 and 12 will later be closed to short-circuit the resistors 14 and 15.

rlhe closing of the contactor 12 is effected by the'closing of the circuit extending from the line conductor 3, through the reversing contactor 61, the conductor 71, the armature 35, the relay 27,the actuating coil 21, the contact member 17, the reversing contactor 58' and the field-magnet winding 84, to the line conductor 4. A branch circuit is, at the same time, established from the relay 27, through the resistor 86, the coil 23, the contact member 18"-, the reversing contactor 58 and the field-magnet winding 84, to the line conductor 4 to reestablish thecircuit of the coil 23 upon the short-circuiting of the coil resistor 6.

.lt will be noted that, in the systems of Figs. 5 and 8, a triple check against starting 22 caused bythe short-circuiting of the the motor in the reverse direction, with the .pointed out that, though ll preferred to einploy the De Camp relay, the invention is not limited thereto, but may be adapted to control systeins embodying the use of ordinary relays. lin Fig. 9, l illustrate one method oi reversal for such a control system. rllhe relays 25, 26 and 27 are here of the ordinary type, each energized by an individual coil 22, 22b and .220. The relay 25 is provided with a, switch member 55a mechanically interlocked therewith, this switch member being open hen the relay is closed and closed when theielay 25 is open.

The reversing contactors, of the interloclred type shown in Figs. 6, 7 and 8, are

gri

troller 7 .is of the form illustrated in Fig. 8, though any equivalent form may be emplo ed.

'lyhe function ofthe various additional switches and contactors above referred to will be explained in connection with the description of the operation which is as follows: Assuming that the controller 7 has been moved to the` left, a circuit is established which extends from the line conductor 3, through the controller 7, the contact member 9b and the actuating coil 8 of the line contactor 5, to the line conductor 4. The line contactor 5 is thereupon closed. This action causes the closing of the circuit eX- tending from the line conductor 3, through the conductor 85, the contactors 90 and 88,

which occupy their closed positions when thev reversing contactors are open, a resistor 91, the actuating coils 22, 22b and 22C, either in series or in parallel, as desired (the parallel relation is here disclosed), and the contactor 5 to the line conductor 4.

The relays 25, 26 and 27 are thereupon immediately opened. The opening of the relay 25 causes the closing of the switch 55a, whereupon a circuit is established from the line conductor 3, through the controller 7, the contact member 9, the actuating coil 63, the switch 55et and the line contactor 5, to the yline conductor I 4. The reversing contactors 59 and 60 are thereupon closed,

which instantlycauses the opening of the contactor 88 to lbreak the circuit o-f the coils 22a, 22b and 22C. The relays 25, 26 and 27, however, will remain open, due to the fact that a new circuit is created for the coils 22a, 22b and 22, in parallel with the resistor 6, whichis now traversed by current through the motor circuit as follows: from the line conductor 3, through the reversing contactor 59, the armature 1, the reversing contactor 60, the resistor 6 and the line contactor 5, to the linecondu-ctor 4.

The circuit in parallel with the resistor 6 for the coils 22a, 221? and 22c includes a resistor 92.. As the mot-or accelerates and its counter-electromotive forcel increases, the voltage across the terminals. of the resistor 6 is decreased, whereupon the relays 25, 26 and 27, which are of different weights, or controlled by springs of different strengths, are

successively closed to cause the closing .of the contactors l0, 1l andy 12 to short-circuit the resistor in a manner that will be well understood from the previous descriptions.

.n The circuits of the actuating coils 19, 20 and 21 may be controlled in the second position of the controller 7. The contactolr 67 creates a holding circuit for the coil 63 so as not to denergize this coil uponthe closing of the relay 25 and the consequent opening of the switch 55a.

To reverse the motor, the controller is actuated tothe right. The motor cannot be restarted in the reverse direction until the reversing -contactors both occupy their open.

positions, as illustrated, because a circuit for the actuating coils 22a, 22"l and 22c must be made through the contactors 88 and 90, as above described, and, furthermore, the circuit of the actuating coil 62 of the reversing contactors 58 and 61 cannot lbe made until the coils 22a, 22b and 22c have been energized, the coil 22a. causing the closing of the switch 55a to establish the circuit of the coil 62. Provision is thus made for preventing. restarting the motor until properconditions obtain.

A study of the system of Fig. 9 will'show that the switch 55a performs the function of the contact members 55, 56 and 57 of Figs. l

e 5, 6 and 8. In the systems of these figures,

it would be possible to substitute Afor the contact members 55, 56 and 57 corresp'nding contact members on the armature 33,

whichwould control the closing of the preliminary circuits when the armature 33 is in the open position. Thus, in the system of .Fig 6, the contact member 55 may be identical 'with the contact member 45 and the contact members 56 may be placed on the other side of the contact member 48, so that the contact members 45 and 48 would be closed when the contact members 45 and 55 would be open, and vice versa. The projection 54 (Fig. 4) could then be omitted. Such changes are thought to be obviousto those 4skilled in the art and are within the scope of m invention. Other changes will be mani est to those skilled in the electrical art.

My invention, furthermore, may' be employed in alternating-current, as well as direct-current systems. I desire, therefore, not to be limited Save as is indicated by the appended claims.

I claim as m invention: 1. The combination with an electric circuit and a pair. of .reversing switches there-r for, of actuating coils for said switches, means for energizing one of sald coils to cause the ,closing of' the correspondingl switch and means for preventing the energization ofsaid other coil fora predetermined length of time after the denergization of said first coil to prevent the closing l system for electric moy resistor in circuit therewith, a plurality of means dependent upon said last named means for governing the closing of said controllin switch. l

5. T e combination with vanelectric motor having an armature, a resistor in'4 cir- Cuit therewith, a pair of reversing switches, a plurality of swltches for short-circuiting said resistor and a relay for each of said switches,I of means for preventing the operation of said motor in the reverse direction with said resistor initially short-cirouited upon the opening of one of said reversing switches and the closing of another of said reversing switches.

6. The combination with an electric motor having an armature, a resistor in circuit therewith, and a switch for controlling the circuit of said motor, of a coil in shunt relation to said resistor, a pair of armatures controlled by saidcoil, means for preventing the closing of one of said armatures until after the closing of said other armature, a switch controlled b said one armature for short-circ'uiting said resistor, and means controlled my said other armature for controllin the closing of said switch.

7 T e combination with an electric motor, a resistor, and a coil in circuit therewith, of an armature controlled by said coil, a switch controlled by said armature for short-circuiting said resistor and said coil, a second coil controlledby said switch for controlling said armature after said first coil is shortcircuited and means for causing said coils to oppose each other upon the reversel of said motor. Y

8. The combination with an electric motor, a resistor in circuit therewith and a pair of reversing switches'for said motor, of a coil, a switch for closing the circuit of said coil when said switch occupies a normal position and for closing the circuit of said motor when it occupies a second position, an armature controlled by said coil for causing said thirdswitch to be actuated to said second position yand means controlled by saidarmature for short-circuiting said resistor.

9. The combination with an electric mofirst coil'into circuit to maintain tor, a resistor in circuit therewith, of means for short-circuiting said resistor, a coil, means controlled by said coil for establishlng the circuit of said motor, means for thereupon denergizing said coil, a second coil for effecting the short-circuiting of said reslstor, said second coil being thereupon deenergized, and means for reinserting said said resistor short-circuited.

10. The combination with an electric motor, a resistor, and a coil in parallel therewith, of an armature controlled by said coil, a switch controlled by said armature for closing the circuit of said motor, a switch controlled by said armature for short-circuitlng said resistor and a second coil controlled by the second switch for controlling said armature after said resistor is shortcircuited.

11. The combination with an electric circuit comprising a translating device and a c oil in parallel therewith, of a pair of armatures controlled by said coil, means controlled by one of said armatures for closin sald circuit and means controlled by the other armature for short-circuiting said translating device.

12. In a reversing system for electric motors, the combination with a motor having an armature and a resistor in circuit therewith, of a plurality of switches for controlling sa'id resistor, a switch for partly closing the circuit of Said motor, means for normally maintainin said last-named switch closed and said rst-named switches open, and means for preventing the reversal of said motor until said switches occupy said normal positions.

13. IThe combination with an electric motor having an armature and a resistor in circuit therewith, of a coilY in shunt relation to said resistor for eii'ecting the short-circuiting 'of said resistor and means for preventing the reversal of said motor until the reversal of the magnetism of said coil.

14. The combination'with an electric motor having an armature, a resistor in circuit therewith, and a switch for short-circuiting said resistor, said switch having an actuating coil, of means for starting said motor and me ns for preventing the short-circuiting of s id resistor after the reversal of'said motor until after the reversal of the magnetism of said coil. l

15. The combination with an electric motor having an armature, a resistorin circuit therewith, and 'a source of current for said motor, yof a switch for closing the circuit of said motor, a plurality of switches for shortcircuiting said resistor, a relay for each of said short-circuiting switches, means controlled by the, voltage of said resistor for closing said relays, means controlled by the refr/2,0157A voltage of said source for maintaining said relays closed, means for opening said circuit-closing switch before reversing the current 1n said armature, said voltage-controlled means thereupon becoming inoperative, means for reclosing said circuit-closing switch and means for preventing the simultaneous closing thereupon of said switches for short-circuiting said resistor.

16. The combination with an electric Inotor, a resistor, a switch for closing the circuit of said motor and a switch for effecting the short-circuiting of said resistor, of an actuating coil for each of said switches, means for energizing the coil of the second switch when said first switch occupies an operative position, and means for energizing the coil of the first switch when said second switch occupies an inoperative position.

17. The combination with an electric motor, a resistor and a switch for closing the circuit of said motor, of a switch for effect-v ing the short-circuiting of said resistor and having an actuating coil, means for energizing said coil when the first switch occupies an inoperative position and means for maintaining said coil energized after said first switch has been actuated to an operative po- Sition.

In testimony whereof, I have hereunto subscribed my name thisl 30th day of July, 1918.

HENRY D. JAMES.

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